Support is requested to investigate behavioral interactions between a native North American treehole mosquito, Aedes triseriatus, and a container-breeding mosquito, Ae. albopictus, that has recently invaded this continent from Asia. The main objective is to obtain information that will permit understanding of population regulation factors in these disease-transmitting mosquitoes. Larval behavioral ecology is not well known and, yet, is critical to formulating population regulation models of vectors. In addition, results of the study will allow for an assessment of the potential success of the invading species in establishing itself within the treehole community. The invading species is capable of transmitting several important exotic viral diseases, and may be capable of extending the range or incidence of diseases that are presently transmitted by North American mosquitoes. Laboratory and field studies will examine interactions which may have potent effects on the population growth of treehole mosquitoes. The following will be investigated for resident species as well as for their influence on the future success of Ae. albopictus as it invades the United States: 1) intra-and interspecific inhibition of egg hatching by abundant large Aedes larvae and mechanisms of egg hatch inhibition; 2) cannibalism within Aedes albopictus populations and the relative vulnerabilities of the native and introduced Aedes species to such attacks; 3) facilitative effects of larvae within a single cohort at moderate densities common in the field; and 4) larval-produced oviposition attractants and repellents and their effect on native sympatric treehole mosquitoes and the introduced Ae. albopictus.